The correct answer is C. 6 electrons, 6 protons, and 8 neutrons.
Explanation
An isotope is a type of atom that is characterized by having a nucleus with a different number of neutrons. Additionally, isotope atoms are those that have the same number of protons in the nucleus (in the case of carbon 6 protons), but different mass numbers. In the case of the isotope of carbon, it has 8 neutrons (2 more neutrons than the regular carbon) and 6 protons in the nucleus, that is, that its mass is 14 (6 protons + 8 neutrons equals 14). According to the above, the correct answer is C.